Bonelli's Eagle

A species in need of help that fascinates us with the air of untamed nature that it transmits.

The Bonelli's Eagle (Aquila fasciata) is one of the birds of prey that is in regression in most of its populations. Worldwide it appears widely distributed throughout southern Europe, northern Africa, the Near and Middle East, India and southern China. The population in the Western Mediterranean is made up of 1,600-2,200 couples, of which 900 (47%) are in countries of the European Union: Spain (733-768 couples, including Mallorca), Italy (34-28 couples in Sicily ) and France (30 couples). The state of conservation of Bonelli's Eagle in Spain will soon be updated since during 2018 the national census of the species will be carried out, at the initiative of AQUILA a-LIFE, in collaboration with SEO / BirdLife.

The decrease of Bonelli's Eagle in Europe contrasts with the stability or even the recovery during this same period of other great raptors, such as the Iberian Imperial Eagle or the Golden Eagle, with which it would share similar problems and threats. The weak point of the Bonelli's Eagle could be its high mortality due to electrocution, because in addition to alighting on top of the supports it also uses - unlike the other big eagles - the lower points of the crosspieces, where the risk is multiplied.

Habitat

The Bonelli's Eagle lives in very variable areas, preferring rocky areas and cliffs in general to build their nests, although they can build them in trees and even in power lines. The feeding of the reproducers is determined by the most abundant prey species in the breeding territories, preferring rabbit, partridge or pigeon to corvids or other birds, lizards or snakes.

Ecology

The young ones disperse to areas with large numbers of prey, where they meet with other young eagles. These movements can be from tens to thousands of kilometres. During the LIFE BONELLI project, the dispersion of two Bonelli's Eagles released in the Community of Madrid to the African continent (Morocco and Senegal) was confirmed.

After spending a variable period in the dispersion zones, the juveniles are recruited either in the breeding population, or in territories already formed, where they replace one of the breeding adults or by founding new or recently abandoned territories. Thanks to the liberations of specimens between 2013 and 2017, LIFE BONELLI has made possible the formation of fifteen Bonelli’s Eagle territories.

Threats

Power lines are the main unnatural threat to the species. Most deaths are caused by electrocution, there are also cases of collision that are less numerous. The data obtained during LIFE BONELLI do not show that direct persecution is one of its main problems, but it is a factor that requires further investigation.

With regard to natural mortality, there are cases of diseases transmitted by other birds (in the case of trichomoniasis) and predation or attacks by other large raptors. During Life Bonelli, cases of attacks on Bonelli's Eagles by Golden Eagle, Imperial Eagle and even among the same species, adult Bonelli's Eagles to juveniles, were confirmed. There have also occurred cases of predation by Eagle Owl.